/*
*  Copyright (c) 2001 Sun Microsystems, Inc.  All rights
*  reserved.
*
*  Redistribution and use in source and binary forms, with or without
*  modification, are permitted provided that the following conditions
*  are met:
*
*  1. Redistributions of source code must retain the above copyright
*  notice, this list of conditions and the following disclaimer.
*
*  2. Redistributions in binary form must reproduce the above copyright
*  notice, this list of conditions and the following disclaimer in
*  the documentation and/or other materials provided with the
*  distribution.
*
*  3. The end-user documentation included with the redistribution,
*  if any, must include the following acknowledgment:
*  "This product includes software developed by the
*  Sun Microsystems, Inc. for Project JXTA."
*  Alternately, this acknowledgment may appear in the software itself,
*  if and wherever such third-party acknowledgments normally appear.
*
*  4. The names "Sun", "Sun Microsystems, Inc.", "JXTA" and "Project JXTA"
*  must not be used to endorse or promote products derived from this
*  software without prior written permission. For written
*  permission, please contact Project JXTA at http://www.jxta.org.
*
*  5. Products derived from this software may not be called "JXTA",
*  nor may "JXTA" appear in their name, without prior written
*  permission of Sun.
*
*  THIS SOFTWARE IS PROVIDED ``AS IS'' AND ANY EXPRESSED OR IMPLIED
*  WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES
*  OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE
*  DISCLAIMED.  IN NO EVENT SHALL THE APACHE SOFTWARE FOUNDATION OR
*  ITS CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
*  SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
*  LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF
*  USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND
*  ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY,
*  OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT
*  OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF
*  SUCH DAMAGE.
*  ====================================================================
*
*  This software consists of voluntary contributions made by many
*  individuals on behalf of Project JXTA.  For more
*  information on Project JXTA, please see
*  <http://www.jxta.org/>.
*
*  This license is based on the BSD license adopted by the Apache Foundation.
*
*  $Id: ExecUnix.java,v 1.1 2004/12/19 23:55:39 gonzo Exp $
*/

package net.jxta.myjxta.util.exec;

import java.io.IOException;
import java.io.InputStream;

/**
 * Class for execs on Unix platforms except Mac OS X.
 *
 * @version $Id: ExecUnix.java,v 1.1 2004/12/19 23:55:39 gonzo Exp $
 *
 * @author james todd [gonzo at jxta dot org]
 * @author mike mcangus [mcangus at jxta dot org]
 */

public final class ExecUnix
    extends BaseExec {

    private static final String[] DELEGATES = { "firefox", "mozilla" };
    private static final String FAIL = "No running";

    private final class Processor {
        private Process process = null;
        private final StringBuffer results = new StringBuffer();
        private int count = 0;

        private class DelegateMonitor
            extends Thread {
            private InputStream in = null;

            DelegateMonitor(InputStream in) {
                this.in = in;
            }

            /**
             * @inheritDoc
             */
            public void run() {
                byte[] b = new byte[1000];
                int c = -1;

                try {
                    while ((c = this.in.read(b)) > 0) {
                        for (int i = 0; i < c; i++) {
                            addResults(String.valueOf((char)(b[i] & 0xFF)));
                        }
                    }
                } catch (IOException ignored) {
                    // ignored exception
                }

                isDone();
            }
        }

        Processor(Process p) {
            this.process = p;
            this.count = 2;

            new DelegateMonitor(this.process.getInputStream()).start();
            new DelegateMonitor(this.process.getErrorStream()).start();
        }

        String getResults() {
            block();

            return this.results.toString();
        }

        void addResults(String results) {
            this.results.append(results);
        }
        
        private synchronized void block() {
            if (this.count > 0) {
                try {
                    while (this.count > 0) {
                        wait();
                    }

                    this.process.waitFor();
                } catch (InterruptedException ignored) {
                    // ignored exception
                }
            }
        }

        synchronized void isDone() {
            if (--this.count <= 0) {
                notify();
            }
        }
    }

    /**
     * Returns the OS-specific process that will execute the specified command.
     * 
     * @param command The command string to be executed.
     * @return the OS-specific process that will execute the specified command.
     */
    public Process exec(String command) {
        Process process = null;
        Processor processor = null;
        boolean isValid = false;

        for (int i = 0; i < DELEGATES.length && ! isValid; i++) {
            try {
                process =
                    Runtime.getRuntime().exec(getRemoteCommand(DELEGATES[i],
                        command));
                processor = new Processor(process);

                process.getOutputStream().close();
            } catch (IOException ignored) {
                // ignored exception
            }

            if (processor != null) {
                isValid = ! (processor.getResults().indexOf(FAIL) >= 0);
            }

            if (! isValid) {
                try {
                    process =
                        Runtime.getRuntime().exec(getCommand(DELEGATES[i], command));
                    processor = new Processor(process);

                    process.getOutputStream().close();
                } catch (IOException ignored) {
                    // ignored exception
                }

                if (processor != null) {
                    isValid = ! (processor.getResults().indexOf(FAIL) >= 0);
                }
            }
        }

        return process;
    }

    private String[] getRemoteCommand(String agent, String s) {
        return new String[]{ agent, "-remote", "openurl(" + s + ")"};
    }

    private String[] getCommand(String agent, String s) {
        return new String[] { agent, s };
    }
}
